Preserve JDoc comments across file renames or path changes

[amit1rrr]

Problem

Currently comments made directly on the notebook (JDoc comments) are tied to the notebook name+path. If the notebook name or path is changed then it's treated as a new document. All the old conversations are not automatically migrated to this new file name / path. While these conversations are available with us, they are not really visible anywhere in the UI. Which is a poor UX.

Solution

Migrate JDoc conversations so they're available even after file rename or path changes. There are two ways to tackle this -

1. See if we can detect file rename from Git history & automatically migrate the conversations
2. If rename detection is not possible (e.g. user has manually deleted & recreated the same file) then offer manual migration mechanism (via UI or support email)